1. Field of the Invention
The present invention relates to a key structure, which features a simplified manufacturing process, reduced costs, and improved waterproof performance, for use in a computer keyboard.
2. Descriptions of the Related Art
The key structure of a conventional computer keyboard comprises a metal board (e.g., an iron board) used as the supporting structure, with a fastening device for each of the key structures either formed directly onto the metal board or molded with a plastic-injecting mold. However, because different keyboards have different key arrangements, both methods require remolding for each different keyboard design, which is not only labor- and time-consuming, but also increases costs.
Taiwan patent No. 454934 published on Sep. 11, 2001 discloses a key switch device. According to the disclosure thereof, the fastening device, which comprises a supporting base and a guiding base, is directly formed onto the substrate (equivalent to the metal board described above). However, this device also needs to be remolded depending on the specific keyboard design. Moreover, a plurality of holes has to be formed in the circuit device disposed on the membrane circuit board for the supporting base and the guiding base to insert into the board. As a result, the manufacturing process is labor- and time-consuming and expensive. The key switch device also has a poor waterproof performance because water may penetrate into the membrane circuit board through the plurality of holes.
Taiwan patent No. 427536 published on Mar. 21, 2001 discloses a notebook computer keyboard. The notebook computer keyboard comprises a hard printed circuit board (PCB), a plurality of contact elements, a plurality of enclosing bases, a plurality of resilient assemblies, and a plurality of key switches. The hard PCB comprises an insulating substrate and a signal-transmitting layer for transmitting a plurality of key signals. The contact elements are disposed above the hard PCB, while the enclosing bases are also disposed above the hard PCB. Each enclosing base has a fastening device and a hole in the middle for accommodating an individual contact element. Each enclosing base is joined together with the hard PCB using the melting method. The resilient assemblies are respectively disposed above the contact elements, and are embedded and fastened into the enclosing bases, so that when the resilient assemblies are pressed, the key signals will be sent out. Each of the key switches includes a key cap and a supporting device. Each supporting device is attached to each fastening device of each enclosing base, while each key cap is disposed above the contact element and the resilient assembly. When a key switch is pressed, the key cap thereof would drive the resilient assembly to move downwards to close the corresponding contact element. Unfortunately, since this notebook computer keyboard uses a hard PCB as the substrate, the manufacturing process thereof is relatively complex due to the complicated multi-layer structure, of the hard PCB. As a result, manufacturing costs are increased.
In view of these shortcomings, many research efforts have been combined with the application of pertinent theories to provide an improved and inventive structure with a reasonable design.